Britain would face shortages of food, fuel and medicine as well as a hard border with Ireland if it leaves the European Union without a deal in October, a leaked batch of official government documents has revealed.

A Cabinet Office dossier obtained by The Sunday Times warned months of border delays could disrupt key supplies to the UK, while social care providers - who would be hit by rising staffing and supply costs - could face a raft a closures.

The paper has published a series of Operation Yellowhammer documents, prepared earlier this month, which shed light on Whitehall's contingency planning for a no-deal Brexit.

The file warned that efforts to avoid the return of a hard border in Ireland are likely to prove "unsustainable" in such a scenario, with warnings of "direct action" and road blockades.

While it said there will be "no new checks, with limited exceptions" on the border, it warns of "significant economic, legal and biosecurity risks" that would make it difficult to keep it open.

The documents stated: “Disruption to key sectors and job losses are likely to result in protests and direct action with road blockages."

Meanwhile the dossier warned government plans to slash import tariffs to 0% under a no-deal may "inadvertently" lead to the closure of two British oil refineries which would bear "significant financial losses".

Traffic disruption caused by border delays could also "affect fuel distribution" and disrupt the supply to London and the south-east.

The fresh supply of food will also "decrease" under a no-deal Brexit, the documents say, while there are concerns complex food production and packaging could be hit by new barriers to trade.

The Yellowhammer dossier also predicts Britain's social care system will struggle to cope with an increase in inflation, which officials say would ramp up staffing and supply costs "and may lead to provider failure, with smaller providers impacted within two-three months and large providers four-six months after exit".

A senior Whitehall source told The Sunday Times: "This is not Project Fear - this is the most realistic assessment of what the public face with no deal. These are likely, basic, reasonable scenarios - not the worst case."

In response, Cabinet Office minister Michael Gove admitted that a no-deal Brexit would cause "bumps in the road", but suggested the 'Operation Yellowhammer' documents were outdated and spelled out only "the very, very worst situation".

Gove said: "It's certainly the case there will be some bumps in the road, some element of disruption in the event of no-deal.

"But the document that has appeared in the Sunday Times was an attempt in the past to work out what the very, very worst situation would be, so we could take steps to mitigate that.

"And we have taken steps, not just to deal with some of the risks, but also to make sure that our economy and our country are better placed than ever to leave the EU on 31 October."

Meanwhile a No.10 source pointed the finger at a group of former ministers who have spoken out against a no-deal Brexit. The group includes ex-Chancellor Philip Hammond and his Cabinet colleague David Gauke.

The source said: "It has been deliberately leaked by a former minister in an attempt to influence discussions with EU leaders.

"Those obstructing preparation are no longer in government, £2bn of extra funding has already made available and Whitehall has been stood up to actually do the work through the daily ministerial meetings.